NEW YORK (TheStreet) -- Pharmacyclics (PCYC) shares are up 10.52% to $254.68 in trading on Thursday after the company announced that rival AbbVie (ABBV) purchased it for $21 billion.

The purchase price translates to $261.25 per share, a 21% premium over the stock's closing price on Tuesday. Speculation that Johnson & Johnson (JNJ) was close to purchasing Pharmacyclics caused the stock to spike in trading on Wednesday.

AbbVie said that after the majority of the leukemia-drug maker's outstanding shares were tendered it would purchase the remaining shares through a second-step merger. The deal is expected to close by the middle of the year.

AbbVie shares are down 3.04% to $58.44 in trading today following the news.

Highlights from the analysis by TheStreet Ratings Team goes as follows: